試題詳解

21. Arthropods invaded land about 100 million years before vertebrates did so. This most clearly implies that
(A) extant terrestrial arthropods are better adapted to terrestrial life than are extant terrestrial vertebrates.
(B) arthropods evolved before vertebrates did.
(C) vertebrates evolved from arthropods.
(D) arthropods have had more time to co-evolve with land plants than have vertebrates.
(E) ancestral arthropods must have been poorly adapted to aquatic life, thus experienced a selective pressure to invade land.